Method of forming sheet metal



Feb. 23, 1965 L L. HOCK 3,170,429

METHOD OF FORMING SHEET METAL Original Filed June 23, 1961 2 Sheets-Sheet 1 as Z0 Z3 Z2 Z1 56.

\/6 INVENTOR.

LAWRENCE L. HOCK ATTORN'YS Feb. 23, 1965 L. L. HOCK METHOD OF FORMING SHEET METAL Original Filed June 23, 1961 2 Sheets-Sheet 2 INVENTOR. A A WRENCE L. HocK A TTOE/VE V5 METHOD OF FORMING SHEET METAL Lawrence L. Hock, Snyder, N.Y., assignor to Niagara Machine & Tool Works, Buffalo, N.Y.

Original application June 23, 1961, Ser. No. 119,091, now Patent No. 3,135,313, dated-June 2, 1964. Divided and this application Feb. 17, 1964, Ser. No. 354,196

1 Claim. (Cl. 113-116) This application is a division of application Serial Number 119,091, filed June 23, 1961, now Patent No.

3,135,313, dated June 2, 1964.

This invention relates to a method of and apparatus for forming sheet metal parts by a succession of metal bending or forming steps carried out by successive strokes of a press brake or other power press provided with a single set of complementary punch and die members.

The method and apparatus of the present invention is directed" primarily to the manufacture of a particular sheet metal product but one which is usually and customarily manufactured locally on a relatively small scale. These articles are known in the art as standing S-cleats and are employed by sheet metal workers mainly in joining square or rectangular duct sections in end to' end relation. I

Various economic factors dictate the general practice of manufacturing S-cleats on a relatively small scale local basis. In any event, presently known and used prior art methods generally entail a series of die forming operations performed in a series of different dies which methods involve multiple setting-up operations, multiple handling'of the work pieces, and other ineificiencies,;not to mention the cost of the several separate sets of dies United States Patent required to perform the successive forming steps of such prior art methods.

The present invention provides a punch and die con- 7 or other power press to perform a series of bending or forming operations without any change in dies, set-up, press stroke or any other condition of adjustment or operation.

The workman picks up a rectangular blank of flat sheet metal or analogous material, subjects the same to various bending or forming operations by successive strokes of the press, in the present instance five such strokes, and lays aside the finished standing S-cleat. Furthermore, the cooperating punch and die members disclosed herein for effecting the novel method of the present invention are extremely simple as to the profiles or configurations of the complementary punch and die surfaces.

Since the standing S-cleats produced by the present method and apparatus are of random length and the forming afiects only the transverse cross section of the workpiece, the work is usually performed in press brakes and the punches and dies are merely continuous integral bars formed with the desired complementary forming surfaces, as is generally the case in punches and dies employed in press brakes.

A single specific die and punch structure and a specific succession of forming steps are illustrated in the accompanying drawings and described in detail in the following specification by way of example but it is to be understood that the principles of the present invention are not limited precisely thereto nor otherwise than as defined in the appended claim.

In the drawings:

FIG. 1 is a transverse cross-sectional view through one form of a pair of cooperating punch and die members of the present invention with the punch raised and a workpiece in position for a first forming operation; I

'FIG. 2 is a view similar to FIG. 1 but showing the punch in lowered position wherein the first forming operation has been effected;

FIGS. 3, 5,7 and 9 are similar to 'FIG.'1, showing the punch member in raised position but showing workpieces disposed for a series of subsequent forming operations; and

FIGS. 4, 6, 8 and 10 are views similar to FIG. 2, showing the punch member in lowered position with respect to the die member and showing the completion of such subsequent series of forming operations. I

Like characters of reference denote like parts throughout the several figures of the drawings and the specific arrangement and contours of the punch and die members will now be described. Referring particularly to FIG. 1, a die member 15 is provided with a V-groove 16 in its upper surface. -In the illustrated instance the rear surface of the V-groove is more vertically disposed than the front surface, as clearly depicted in the drawing.

The flat upper portion of the die surface'rearwardly of the v-groove 16, designated 17', is sloped slightly so that the same is substantially at a right angle to the rear surface of the V-groove 16. The front top surface of die block 15 forwardly of V-groove 16 may be generally horizontal, as shown.

The punch member is designated 20 and is provided with a V-formation 21 which is complementary to the V- groove 16. The under surface of punch member 20 just rearwardly of the V-formation 21, designated 22 in FIG. 1, is at right angles to the rear surface of V-formation 21 and is consequently parallel to the upper rear surface 17 of die block 15. Rearwardly ofthe surface 22 punch member 20 is offset to provide a further surface 23 at 7 right angles to the rear surface of V-formation 21 and parallel to the surface .22 of the punch member.

As shown in FIG. 2, the punch and die members 20 and '15 may be provided with conventional tongues designated 25 and 26 respectively for securing the punch and die members in a conventional press brake or like power press. The foregoing relatively, simple punch and die setup is adapted to perform, in the present instance, a series .of five successive bending or metal-forming operations on a single workpiece with a single handling thereof and without any change in set-up to produce a finished S cleat such as is shown at 28 in FIG. 10.

These successive operations are performed by successive press strokes and despite the differing character of the successive bending operations the design and arrangement of the punch and die members is such that the various operations are each performed with like strokes of the punch member. That is, the punch member descends a constant fixed distance into the die member on each stroke so that a workman need only successively reposition the workpiece between each bending or forming operation until the five operations of the present set-up have been performed and the finished piece produced.

It is to be understood that S-cleats are generally elongated and of various lengths and that the several cross sectional views thereof shown herein are transverse. Accordingly, FIG. 1 shows a rectangular blank or workpiece 30, the width or smaller dimension thereof being shown in FIG. 1 in the initial position of the blank for the first forming operation.

The proportions of the V-groove 16 and complementary V-formation 21, their relative positions considered from front to rear (from left to right as viewed in FIG. 1), and the depth of travel of the punch member 20, are all such that in the lower or closed position of the punch member the rear or left-hand face of the V-forma- 3 tion 21 as viewed in the drawings and the corresponding left-hand or rear face of the groove 16 are parallel and spaced approximately a metal thickness whereas the front or right-hand faces of the groove 16- and V-formation 21 are likewise parallel but at a substantially greater distance from each other. Furthermore, theleclge 22 of the punch member 20 is arranged to approach the corresponding upper face portion 17 of die member 15 to 1 Within substantially one metal. thickness when the punchstroke produces a rounded return bent formation, as

clearly illustrated in FIG. 4.

The operation illustrated in FIGS. 5 and 6 is substantially the same as that of FIGS. 1 and 2 expecting'that.

the opposite edge of the blank or workpiece 36 is obliquely flanged as at 35 and in the present instance in I the opposite direction. I

In the succeeding forming operation illustrated in FIGS. 7 and 8 the workpiece is formed into substantially Z-shapeand at the same time the oblique flange 35 is formed into return bent form, again somewhat rounded as in the case of the return bent formation of flange 31, in this instance *by reason of the relative spacing of the surface 23 of the punch member with respect to the companion surface 17 of the dieblock 15.

The generally z-form of the workpiece producedas illustrated in FIG. 8 provides a right-angle bend at the upper rear edge of the V-groove 16 which produces substantially the finished form of a medial flange 37 of the finished S-cleat, as shown in FIG. 10. At the same time tionto produce the substantially T-form of the finished S cleat illustrated in FIG. 10.

Here again the spacing of the front face of ridge formation 21 of punch member 20 and the corresponding front face of V-groove 16 in die block 15 results in a rounded edge in the return bent formation. The front face of punch member 20 is notched at the base of the V-formation 21 to clear the workpiece as the same flanges up in the various operations and to provide a ledge 58 which, in the final forming operation illustrated in FIGS. 9 and 10, engages the return bend which was formed in the operation illustrated in FIGS. '1 and 2 and holds the workpiece against slipping upwardly during the final forming operation illustrated in FIG. 10. The finished S cleat is'thus provided with three smoothly rounded edges which by reason of their'mode-of formation are of substantially the'samef radius or thickness across the aforesaid return bends. i 5

In a method of fabricating a sheet metal article of generally T-shaped cross section with return bent ed'ges by repeated strokes of a pair of forming die members having a V-groove' in one member and a generally cornplernentary ridge formation in the other-with the dies arranged so that in closed position there is substantially a metal thickness space between the rear surfaces of said groove and ridge formation and a substantially greater space at the front surfaces thereof, the steps of forming a V adjacent to a margin of a sheet metal workpiece by bending the same between said V-groove and ridge formation, flattening the same to return bent form between said front surfaces, forming a second V adjacent to the opposite margin of said workpiece in like manner to the first step, simultaneously forming a Z in the medial portion of the workpiece by cooperation of the apex of said ridge formation and the rear edge surface of said V-groove andflattening said second formed V between the surfaces of said members rearwardly of said groove and ridge formation, and finally fiatteningfone of the angles of said .Z-forrnation between the front surfaces of said groove and ridge formation to produce an article of T-shaped cross section.

References Cited by the Examiner UNITED STATES PATENTS 658,077 9/00 Thomas 153 21 2,847,052 8/58 Handman- 153 21 3,034,559 5/62 slam '153 21 FOREIGN PATENTS 626,805 7/49 Great Britain.

CHARLES W. LANHAM, Primary Examiner, 

